Several machines are known which use a source of air under pressure, instead of mechanical elements, for lifting fruit or similar objects and propelling them towards an inclined ramp. However, none of these machines are able to provide, at the present time, complete satisfaction because their solutions are adopted with regard to the arrangement of the inclined ramp and the fluid blast enclosure.
According to a first technique, described particularly in U.S. Pat. Nos. 3,675,405 and 4,194,346, and French patent application No. 2,531,305, the inclined ramp and the fluid discharge casing are arranged transversly with respect to the direction of advance or travel of the machine. As a result, only the fruit which is found between the lower edge of the inclined ramp and the opening of the fluid discharge nozzle are gathered. In order to blow or sweep over a useful zone of greater size and thus avoid a significant number of passes over a field, the lower edge of the ramp is thus relatively distant from the nozzle of the blower. Therefore it is necessary to provide a blower of great power and to orient the nozzle of the blower in such a matter as to deliver an air flow which is essential horizontal.
In addition to the necessity of providing a very powerful blower, this solution leads to several disadvantages. The flow being horizontal, the fruits arranged beneath the average level of the ground are not collected. Further, by reason of the power of the blower, there are certain risks of tearing up the ground in proximity to the discharge of the blower. This type of machine is particularly unsuitable for use over vegetated ground. In effect, the flow of air has a tendency to lay down the vegetation which then acts as a deflector and therefore causes the flow of air to move upwardly, greatly reducing the percentage of fruits collected.
According to a second technique, particularly described as a variation in French patent application 2,531,305, the inclined ramp and the blower casing are arranged parallel to the direction of advance of the machine, with the direction of the flow of air being the same as the direction of advance of the machine. The lower front edge of the inclined ramp passes over the fruit before the fruit is exposed to the flow of air, and the ramp is, as a result, articulated about a transverse axis. The disadvantage relating to the significant distance separating the mouth of the blower discharge from the inclined ramp is thus overcome.
However, this technique also presents several disadvantages. The fact that the inclined ramp rises up when it encounters the fruit or natural obstacles generates a sizeable loss of air flow which seeps under the ramp and has a tendency to repel the fruit found immediately there beneath. Moreover, on ground having a lot of debris, the apparatus quickly produces behind the inclined ramp an accumulation of debris which the ramp is not able to pass over. Finally, during use of this machine in hilly terrain, the lower edge of the ramp is not in contact with the ground over its entire length, and a sizeable portion of air flow seeps under the ramp. In this latter case, the fruit found at the average level of the ground is not collected.
Accordingly, a primary object of the present invention is therefore to overcome the disadvantages of known machines while providing a process and machine able to permit collection fruit with equal efficiency regardless of the nature of the terrain (vegetated, hilly, loaded with debris, wet . . . ).
Another object of the invention is to provide a machine able to carry out a separation for eliminating fruit of very small dimensions, twigs, leaves and other debris.
Another object is to provide a machine in which the pieces or moving parts presenting risks for the operator are reduced in number and easily accessible.